(a) Field of the Invention
The present invention relates to a condenser of the plate, tube or other type.
(b) Description of the Prior Art
Generally, of the plate type condensers now in use, many have been developed from the plate type condenser for liquid-to-liquid use only. In improving the heat transmitting performance of such condensers, what becomes a problem is the film coefficient which indicates the ease of heat transmission in a heat transmitting surface. The film coefficient is defined as the heat conductivity of the liquid film divided by the thickness of the liquid film, i.e., it is determined by the condition in which condensate adheres to the heat transmitting surface. Thus, if steam is fed to a heat transmitting surface constituting a steam passageway, a film of condensate is formed on the entire area of the heat transmitting surface. As condensation continues to proceed, the condensate film becomes gradually thicker and eventually flows down along the heat transmitting surface under its own weight and/or by the dynamic pressure of the steam. This liquid film merges with other liquid films at lower levels to become a thick downflow liquid film and the heat transmitting surface covered with this downflow liquid film is prevented from contact with steam, and since the thickness of the liquid film is increased, the film coefficient in that region of the surface is condiderably decreased, greatly lowering the heat transmitting performance. Therefore, in order to improve the heat transmitting performance of the entire heat transmitting surface, it is necessary to take measures to minimize the area of the downflow liquid film and prevent its thickness from being greatly increased.
As an example of such measure, the applicant has proposed along with the present invention a heat transmitting surface having longitudinal grooves arranged in several lines on the condensing and heat transmitting surface and inclined water collectors disposed at several places on said longitudinal grooves. According to this arrangement, the condensate on the heat transmitting surface is collected in the valleys of the longitudinal grooves by the action of surface tension and flows down along said valleys, and when its amount reaches a certain value, it flows into the water collectors. That is, the downflow liquid films are concentrated in the valleys of the longitudinal grooves, so that the film coefficient is maintained high as a whole. Further, where the effect of the longitudinal grooves extends, the presence of such water collectors is not required, and hence the number of such water collectors can be correspondingly reduced. However, such water collectors are absolutely necessary and require a corresponding space for arrangement.
At any rate, such conventional condenser requires water collectors on the heat transmitting surface for collecting the condensate on the way and allowing it to flow down for discharge. Such water collectors have to be arranged in a net pattern on the heat transmitting surface, thus occupying a considerable space in relation to the heat transmitting surface. From the standpoint of space, therefore, there has been a problem in connection with improving the overall coefficient of heat transfer.